diff --git a/README.md b/README.md
index d6a5a1b..156b305 100644
--- a/README.md
+++ b/README.md
@@ -1,13 +1,16 @@
 [![wikidata](https://raw.githubusercontent.com/maxlath/wikidata-cli/master/assets/wikidata_logo_alone.jpg)](https://wikidata.org)
 
-# Wikidata [![Build Status](https://travis-ci.org/freearhey/wikidata.svg?branch=master)](https://travis-ci.org/freearhey/wikidata)
+# Wikidata
 
 Wikidata provides a API for searching and retrieving data from [wikidata.org](https://www.wikidata.org).
 
+Fork of https://github.com/freearhey/wikidata
+@todo: consider https://github.com/freearhey/wikidata/compare/master...JamesFrost:wikidata:master
+
 ## Installation
 
 ```sh
-composer require freearhey/wikidata
+composer require survos/wikidata
 ```
 
 ## Usage
@@ -208,7 +211,7 @@ vendor/bin/phpunit
 
 ### Contribution
 
-If you find a bug or want to contribute to the code or documentation, you can help by submitting an [issue](https://github.com/freearhey/wikidata/issues) or a [pull request](https://github.com/freearhey/wikidata/pulls).
+If you find a bug or want to contribute to the code or documentation, you can help by submitting an [issue](https://github.com/survos/wikidata/issues) or a [pull request](https://github.com/freearhey/wikidata/pulls).
 
 ### License
 
diff --git a/composer.json b/composer.json
index bea5296..11377a0 100644
--- a/composer.json
+++ b/composer.json
@@ -1,23 +1,28 @@
 {
-  "name": "freearhey/wikidata",
+  "name": "survos/wikidata",
   "description": "A PHP client for working with Wikidata API.",
   "keywords": [
     "wikidata",
     "client",
     "php"
   ],
-  "homepage": "https://github.com/freearhey/wikidata",
+  "homepage": "https://github.com/survos/wikidata",
   "license": "MIT",
-  "version": "3.6.0",
+  "version": "5.0.0",
   "authors": [
     {
       "name": "Arhey",
       "role": "developer"
+    },
+    {
+      "name": "tacman",
+      "role": "developer"
     }
   ],
   "require": {
-    "tightenco/collect": "^8.0",
-    "guzzlehttp/guzzle": "^7.0"
+    "php": "^8.2",
+    "illuminate/collections": "^10.0|^11.0",
+    "symfony/http-client": "^6.4||^7.0"
   },
   "autoload": {
     "psr-4": {
@@ -36,6 +41,8 @@
     ]
   },
   "require-dev": {
-    "phpunit/phpunit": "^9.0"
+    "phpunit/phpunit": "^9.0",
+    "phpstan/phpstan": "^1.10",
+    "rector/rector": "^1.1"
   }
 }
diff --git a/phpstan.neon b/phpstan.neon
new file mode 100644
index 0000000..562fa66
--- /dev/null
+++ b/phpstan.neon
@@ -0,0 +1,5 @@
+parameters:
+    level: 4
+#    inferPrivatePropertyTypeFromConstructor: true
+    paths:
+        - ./src/
diff --git a/rector.php b/rector.php
new file mode 100644
index 0000000..0174aa4
--- /dev/null
+++ b/rector.php
@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+use Rector\Config\RectorConfig;
+use Rector\TypeDeclaration\Rector\ClassMethod\AddVoidReturnTypeWhereNoReturnRector;
+use Rector\TypeDeclaration\Rector\Property\TypedPropertyFromAssignsRector;
+use Rector\Set\ValueObject\SetList;
+
+return RectorConfig::configure()
+    ->withPaths([
+        __DIR__ . '/src',
+        __DIR__ . '/tests',
+    ])
+    // uncomment to reach your current PHP version
+    ->withPhpSets(php82: true)
+    ->withSets([
+        SetList::TYPE_DECLARATION,
+    ])
+    ->withRules([
+        TypedPropertyFromAssignsRector::class,
+        AddVoidReturnTypeWhereNoReturnRector::class,
+    ]);
diff --git a/src/ApiClient.php b/src/ApiClient.php
index 08c38ff..175947f 100644
--- a/src/ApiClient.php
+++ b/src/ApiClient.php
@@ -2,86 +2,83 @@
 
 namespace Wikidata;
 
-use GuzzleHttp\Client;
+use Illuminate\Support\Collection;
+use Symfony\Component\HttpClient\HttpClient;
+use Symfony\Contracts\HttpClient\HttpClientInterface;
 
 class ApiClient
 {
-  const API_ENDPOINT = 'https://www.wikidata.org/w/api.php';
+    public const API_ENDPOINT = 'https://www.wikidata.org/w/api.php';
 
-  /**
-   * @var string Value Id
-   */
-  private $client;
 
-  /**
-   * @param array $data
-   */
-  public function __construct()
-  {
-    $this->client = new Client();
-  }
+    public function __construct(private ?HttpClientInterface $client=null)
+    {
+        if (!$this->client) {
+            $this->client = HttpClient::create();
+        }
+    }
 
-  /**
-   * Get all entities by their ids from wikidata api
-   *
-   * @param string $ids The IDs of the entities to get the data from (eg.: Q2)
-   * @param string $lang Language (default: en)
-   * @param string $props Array of the properties to get back from each entity (supported: aliases, claims, datatype, descriptions, info, labels, sitelinks, sitelinks/urls)
-   *
-   * @return \Illuminate\Support\Collection
-   */
-  public function getEntities($ids, $lang = 'en', $props = [])
-  {
-    $ids = is_array($ids) ? implode('|', $ids) : $ids;
+    /**
+     * Get all entities by their ids from wikidata api
+     *
+     * @param array|string $ids The IDs of the entities to get the data from (eg.: Q2, Q2|Q3)
+     * @param string $lang Language (default: en)
+     * @param array|string $props Array of the properties to get back from each entity (supported: aliases, claims, datatype, descriptions, info, labels, sitelinks, sitelinks/urls)
+     *
+     * @return \Illuminate\Support\Collection
+     */
+    public function getEntities(array|string $ids, string $lang = 'en', array|string $props = []): Collection
+    {
+        $ids = is_array($ids) ? implode('|', $ids) : $ids;
 
-    $props = $props ? implode('|', $props) : null;
+        $props = $props ? implode('|', $props) : null;
 
-    $response = $this->client->get(self::API_ENDPOINT, [
-      'query' => [
-        'action' => 'wbgetentities',
-        'format' => 'json',
-        'languages' => $lang,
-        'ids' => $ids,
-        'sitefilter' => $lang . 'wiki',
-        'props' => $props,
-      ],
-    ]);
+        $response = $this->client->request('GET', self::API_ENDPOINT, [
+            'query' => [
+                'action' => 'wbgetentities',
+                'format' => 'json',
+                'languages' => $lang,
+                'ids' => $ids,
+                'sitefilter' => $lang . 'wiki',
+                'props' => $props,
+            ],
+        ]);
 
-    $results = json_decode($response->getBody(), true);
+        $results = json_decode($response->getContent(), true);
 
-    $data = isset($results['entities']) ? $results['entities'] : [];
+        $data = $results['entities'] ?? [];
 
-    return collect($data);
-  }
+        return collect($data);
+    }
 
-  /**
-   * Searches for entities using labels and aliases
-   *
-   * @param string $query
-   * @param string $lang Language (default: en)
-   * @param string $limit Max count of returning items (default: 10)
-   *
-   * @return \Illuminate\Support\Collection
-   */
-  public function searchEntities($query, $lang = 'en', $limit = 10)
-  {
-    $response = $this->client->get(self::API_ENDPOINT, [
-      'query' => [
-        'action' => 'wbsearchentities',
-        'format' => 'json',
-        'strictlanguage' => true,
-        'language' => $lang,
-        'uselang' => $lang,
-        'search' => $query,
-        'limit' => $limit,
-        'props' => '',
-      ],
-    ]);
+    /**
+     * Searches for entities using labels and aliases
+     *
+     * @param string $query
+     * @param string $lang Language (default: en)
+     * @param int $limit Max count of returning items (default: 10)
+     *
+     * @return \Illuminate\Support\Collection
+     */
+    public function searchEntities($query, $lang = 'en', int $limit = 10)
+    {
+        $response = $this->client->request('GET', self::API_ENDPOINT, [
+            'query' => [
+                'action' => 'wbsearchentities',
+                'format' => 'json',
+                'strictlanguage' => true,
+                'language' => $lang,
+                'uselang' => $lang,
+                'search' => $query,
+                'limit' => $limit,
+                'props' => '',
+            ],
+        ]);
 
-    $results = json_decode($response->getBody(), true);
+        $results = json_decode($response->getContent(), true);
 
-    $data = isset($results['search']) ? $results['search'] : [];
+        $data = $results['search'] ?? [];
 
-    return collect($data);
-  }
+        return collect($data);
+    }
 }
diff --git a/src/Entity.php b/src/Entity.php
index dc5aae4..a240e09 100644
--- a/src/Entity.php
+++ b/src/Entity.php
@@ -2,6 +2,7 @@
 
 namespace Wikidata;
 
+use Illuminate\Support\Collection;
 use Wikidata\Property;
 
 class Entity
@@ -11,11 +12,6 @@ class Entity
    */
   public $id;
 
-  /**
-   * @var string Entity language
-   */
-  public $lang;
-
   /**
    * @var string Entity label
    */
@@ -34,20 +30,17 @@ class Entity
   /**
    * @var string Entity description
    */
-  public $description;
+  public string $description;
 
-  /**
-   * @var \Illuminate\Support\Collection Collection of entity properties
-   */
-  public $properties = [];
+  public Collection $properties;
 
   /**
    * @param array $data
    * @param string $lang
    */
-  public function __construct($data, $lang)
+  public function __construct($data, public $lang)
   {
-    $this->lang = $lang;
+    $this->properties = new Collection();
     $this->parseData($data);
   }
 
@@ -56,7 +49,7 @@ public function __construct($data, $lang)
    *
    * @param array $data
    */
-  private function parseData($data)
+  private function parseData(array $data): void
   {
     $lang = $this->lang;
     $site = $lang . 'wiki';
@@ -71,19 +64,19 @@ private function parseData($data)
   /**
    * Parse entity properties from sparql result
    *
-   * @param array $data
+   * @param Collection $data
    */
-  public function parseProperties($data)
+  public function parseProperties(array|Collection $data): void
   {
-    $collection = collect($data)->groupBy('prop');
-    $this->properties = $collection->mapWithKeys(function ($item) {
+    $collection = (new Collection($data))->groupBy('prop');
+    $this->properties = $collection->mapWithKeys(function ($item): array {
       $property = new Property($item);
 
       return [$property->id => $property];
     });
   }
 
-  public function toArray()
+  public function toArray(): array
   {
     return [
       'id' => $this->id,
diff --git a/src/Property.php b/src/Property.php
index b15d3e9..f3a69fb 100644
--- a/src/Property.php
+++ b/src/Property.php
@@ -31,18 +31,16 @@ public function __construct($data)
 
   /**
    * Parse input data
-   * 
+   *
    * @param array $data
    */
-  private function parseData($data)
+  private function parseData($data): void
   {
     $grouped = collect($data)->groupBy('statement');
     $flatten = $grouped->flatten(1);
 
     $this->id = get_id($flatten[0]['prop']);
     $this->label = $flatten[0]['propertyLabel'];
-    $this->values = $grouped->values()->map(function($v) {
-      return new Value($v->toArray());
-    });
+    $this->values = $grouped->values()->map(fn($v): \Wikidata\Value  => new Value($v->toArray()));
   }
 }
diff --git a/src/Qualifier.php b/src/Qualifier.php
index ceeb59b..bbafe5c 100644
--- a/src/Qualifier.php
+++ b/src/Qualifier.php
@@ -32,7 +32,7 @@ public function __construct($data)
    * 
    * @param array $data
    */
-  private function parseData($data)
+  private function parseData(array $data): void
   {
     $this->id = get_id($data['qualifier']);
     $this->label = $data['qualifierLabel'];
diff --git a/src/SearchResult.php b/src/SearchResult.php
index 56d3d81..f0f0a59 100644
--- a/src/SearchResult.php
+++ b/src/SearchResult.php
@@ -9,11 +9,6 @@ class SearchResult
    */
   public $id;
 
-  /**
-   * @var string
-   */
-  public $lang;
-
   /**
    * @var string
    */
@@ -36,19 +31,19 @@ class SearchResult
 
   /**
    * @param array $data
+   * @param string $lang
    */
-  public function __construct($data, $lang = 'en')
+  public function __construct($data, public $lang = 'en')
   {
     $this->parseData($data);
-    $this->lang = $lang;
   }
 
-  private function parseData($data)
+  private function parseData($data): void
   {
-    $this->id = isset($data['id']) ? $data['id'] : null;
-    $this->label = isset($data['label']) ? $data['label'] : null;
-    $this->aliases = isset($data['aliases']) ? $data['aliases'] : [];
-    $this->description = isset($data['description']) ? $data['description'] : null;
-    $this->wiki_url = isset($data['wiki_url']) ? $data['wiki_url'] : null;
+    $this->id = $data['id'] ?? null;
+    $this->label = $data['label'] ?? null;
+    $this->aliases = $data['aliases'] ?? [];
+    $this->description = $data['description'] ?? null;
+    $this->wiki_url = $data['wiki_url'] ?? null;
   }
 }
diff --git a/src/SparqlClient.php b/src/SparqlClient.php
index c170d03..8443706 100644
--- a/src/SparqlClient.php
+++ b/src/SparqlClient.php
@@ -3,32 +3,41 @@
 namespace Wikidata;
 
 use Exception;
-use GuzzleHttp\Client;
+use Symfony\Component\HttpClient\HttpClient;
+use Symfony\Contracts\HttpClient\HttpClientInterface;
 
 class SparqlClient {
 
+    public function __construct(
+        private ?HttpClientInterface $client=null
+    )
+    {
+        if (!$this->client) {
+            $this->client = HttpClient::create();
+        }
+    }
+
   /**
    * Limit on how long can be the query to be sent by GET.
    */
-  const MAX_GET_SIZE = 2048;
+  public const MAX_GET_SIZE = 2048;
 
   /**
    * SPARQL endpoint URL
    * @var string
    */
-  const SPARQL_ENDPOINT = 'https://query.wikidata.org/sparql';
+  public const SPARQL_ENDPOINT = 'https://query.wikidata.org/sparql';
 
   /**
    * Query timeout (seconds)
-   * @var int
    */
-  private $timeout = 30;
+  private int $timeout = 30;
 
   /**
    * Request method
-   * @var array
+   * @var string
    */
-  private $method = 'GET';
+  private string $method = 'GET';
 
   /**
    * Query SPARQL endpoint
@@ -38,7 +47,6 @@ class SparqlClient {
    *
    * @return array List of results, one row per array element
    *               Each row will contain fields indexed by variable name.
-   * @throws SparqlException
    */
   public function execute( $query, $rawData = false ) {
 
@@ -47,9 +55,7 @@ public function execute( $query, $rawData = false ) {
       $this->method = 'POST';
     }
 
-    $client = new Client();
-
-    $response = $client->request( $this->method, self::SPARQL_ENDPOINT, [
+    $response = $this->client->request( $this->method, self::SPARQL_ENDPOINT, [
         'query' => [
           "query" => $query,
           "format" => "json",
@@ -63,7 +69,7 @@ public function execute( $query, $rawData = false ) {
       throw new Exception( 'HTTP Error' );
     }
 
-    $result = $response->getBody();
+    $result = $response->getContent();
 
     $data = json_decode( $result, true );
 
@@ -85,7 +91,7 @@ public function execute( $query, $rawData = false ) {
    *
    * @return array List of results, one row per element.
    */
-  private function extractData( $data, $rawData = false ) {
+  private function extractData( array $data, $rawData = false ): array {
     $result = [];
     if ( $data && !empty( $data['results'] ) ) {
       $vars = $data['head']['vars'];
diff --git a/src/Value.php b/src/Value.php
index 2215dd0..31aebd9 100644
--- a/src/Value.php
+++ b/src/Value.php
@@ -34,11 +34,11 @@ public function __construct($data)
    *
    * @param array $data
    */
-  private function parseData($data)
+  private function parseData(array $data): void
   {
     $this->id = get_id($data[0]['propertyValue']);
     $this->label = $data[0]['propertyValueLabel'];
-    $this->qualifiers = collect($data)->map(function($item) {
+    $this->qualifiers = collect($data)->map(function(array $item): ?\Wikidata\Qualifier {
       if($item['qualifier']) {
         return new Qualifier($item);
       }
diff --git a/src/Wikidata.php b/src/Wikidata.php
index d14abfb..08da2ef 100644
--- a/src/Wikidata.php
+++ b/src/Wikidata.php
@@ -15,11 +15,11 @@ class Wikidata
    *
    * @param string $query
    * @param string $lang Language (default: en)
-   * @param string $limit Max count of returning items (default: 10)
+   * @param int $limit Max count of returning items (default: 10)
    *
    * @return \Illuminate\Support\Collection Return collection of \Wikidata\SearchResult
    */
-  public function search($query, $lang = 'en', $limit = 10)
+  public function search($query, $lang = 'en', int $limit = 10)
   {
     $client = new ApiClient();
 
@@ -29,7 +29,7 @@ public function search($query, $lang = 'en', $limit = 10)
 
     $entities = $client->getEntities($ids, $lang, ['sitelinks/urls', 'aliases', 'descriptions', 'labels']);
 
-    $output = $entities->map(function ($item) use ($lang) {
+    $output = $entities->map(function ($item) use ($lang): \Wikidata\SearchResult {
       $entity = new Entity($item, $lang);
       return new SearchResult($entity->toArray(), $lang);
     });
@@ -43,11 +43,11 @@ public function search($query, $lang = 'en', $limit = 10)
    * @param string $property Wikidata ID of property (e.g.: P646)
    * @param string $value String value of property or Wikidata entity ID (e.g.: Q11696)
    * @param string $lang Language (default: en)
-   * @param string $limit Max count of returning items (default: 10)
+   * @param int $limit Max count of returning items (default: 10)
    *
    * @return \Illuminate\Support\Collection Return collection of \Wikidata\SearchResult
    */
-  public function searchBy($property, $value = null, $lang = 'en', $limit = 10)
+  public function searchBy(string $property, $value = null, $lang = 'en', int $limit = 10)
   {
     if (!is_pid($property)) {
       throw new Exception("First argument in searchBy() must be a valid Wikidata property ID (e.g.: P646).", 1);
@@ -69,15 +69,13 @@ public function searchBy($property, $value = null, $lang = 'en', $limit = 10)
 
     $data = $client->execute($query);
 
-    $ids = collect($data)->map(function ($data) {
-      return str_replace("http://www.wikidata.org/entity/", "", $data['item']);
-    })->toArray();
+    $ids = collect($data)->map(fn($data): string|array => str_replace("http://www.wikidata.org/entity/", "", $data['item']))->toArray();
 
     $client = new ApiClient();
 
     $entities = $client->getEntities($ids, $lang, ['sitelinks/urls', 'aliases', 'descriptions', 'labels']);
 
-    $output = $entities->map(function ($data) use ($lang) {
+    $output = $entities->map(function ($data) use ($lang): \Wikidata\SearchResult {
       $entity = new Entity($data, $lang);
       return new SearchResult($entity->toArray(), $lang);
     });
@@ -93,7 +91,7 @@ public function searchBy($property, $value = null, $lang = 'en', $limit = 10)
    *
    * @return \Wikidata\Entity Return entity
    */
-  public function get($entityId, $lang = 'en')
+  public function get(string $entityId, string $lang = 'en'): \Wikidata\Entity
   {
     if (!is_qid($entityId)) {
       throw new Exception("First argument in get() must by a valid Wikidata entity ID (e.g.: Q646).", 1);
@@ -120,9 +118,7 @@ public function get($entityId, $lang = 'en')
 
     $data = $client->execute($query);
 
-    if (isset($data)) {
-      $entity->parseProperties($data);
-    }
+    $entity->parseProperties($data);
 
     return $entity;
   }
diff --git a/src/helpers.php b/src/helpers.php
index bf12d43..305d1ca 100644
--- a/src/helpers.php
+++ b/src/helpers.php
@@ -1,4 +1,5 @@
 <?php
+// @todo:move to namespace, etc.  NOT global!
 
 /**
  * Check if given string is valid Wikidata entity ID
@@ -7,9 +8,11 @@
  *
  * @return bool Return true if string is valid or false
  */
-function is_qid($value)
-{
-    return preg_match("/^Q[0-9]+/", $value);
+if (!function_exists('is_qid')) {
+    function is_qid($value): int|false
+    {
+        return preg_match("/^Q[0-9]+/", (string) $value);
+    }
 }
 
 /**
@@ -19,9 +22,11 @@ function is_qid($value)
  *
  * @return bool Return true if string is valid or false
  */
-function is_pid($value)
-{
-    return preg_match("/^P[0-9]+/", $value);
+if (!function_exists('is_pid')) {
+    function is_pid($value): int|false
+    {
+        return preg_match("/^P[0-9]+/", (string) $value);
+    }
 }
 
 /**
@@ -31,9 +36,12 @@ function is_pid($value)
  *
  * @return string
  */
-function get_id($string)
-{
-  preg_match('/(Q|P)\d+/i', $string, $matches);
+if (!function_exists('get_id')) {
 
-  return !empty($matches) ? $matches[0] : $string;
+    function get_id($string)
+    {
+        preg_match('/(Q|P)\d+/i', (string) $string, $matches);
+
+        return !empty($matches) ? $matches[0] : $string;
+    }
 }
diff --git a/tests/Unit/EntityTest.php b/tests/Unit/EntityTest.php
index f5a6910..081d34b 100644
--- a/tests/Unit/EntityTest.php
+++ b/tests/Unit/EntityTest.php
@@ -15,53 +15,53 @@ public function setUp(): void
     $this->entity = new Entity($this->dummy[0], $this->lang);
   }
 
-  public function testGetEntityId()
+  public function testGetEntityId(): void
   {
     $this->assertEquals($this->dummy[0]['id'], $this->entity->id);
   }
 
-  public function testGetEntityLang()
+  public function testGetEntityLang(): void
   {
     $this->assertEquals($this->lang, $this->entity->lang);
   }
 
-  public function testGetEntityLabel()
+  public function testGetEntityLabel(): void
   {
     $this->assertEquals($this->dummy[0]['labels'][$this->lang]['value'], $this->entity->label);
   }
 
-  public function testGetEntityDescription()
+  public function testGetEntityDescription(): void
   {
     $this->assertEquals($this->dummy[0]['descriptions'][$this->lang]['value'], $this->entity->description);
   }
 
-  public function testGetWikiUrl()
+  public function testGetWikiUrl(): void
   {
     $this->assertEquals($this->dummy[0]['sitelinks'][$this->lang . 'wiki']['url'], $this->entity->wiki_url);
   }
 
-  public function testGetEntityAliases()
+  public function testGetEntityAliases(): void
   {
     $aliases = collect($this->dummy[0]['aliases'][$this->lang])->pluck('value')->toArray();
 
     $this->assertEquals($aliases, $this->entity->aliases);
   }
 
-  public function testGetEntityWithoutAliases()
+  public function testGetEntityWithoutAliases(): void
   {
     $entity = new Entity($this->dummy[1], 'en');
 
     $this->assertEquals([], $entity->aliases);
   }
 
-  public function testGetEntityProperties()
+  public function testGetEntityProperties(): void
   {
     $this->entity->parseProperties($this->dummyProperties);
 
     $properties = $this->entity->properties;
 
-    $this->assertInstanceOf('Illuminate\Support\Collection', $properties);
+    $this->assertInstanceOf(\Illuminate\Support\Collection::class, $properties);
 
-    $this->assertInstanceOf('Wikidata\Property', $properties->first());
+    $this->assertInstanceOf(\Wikidata\Property::class, $properties->first());
   }
 }
diff --git a/tests/Unit/PropertyTest.php b/tests/Unit/PropertyTest.php
index 0df05e7..e93655e 100644
--- a/tests/Unit/PropertyTest.php
+++ b/tests/Unit/PropertyTest.php
@@ -13,24 +13,24 @@ public function setUp(): void
     $this->property = new Property($this->dummyProperties);
   }
 
-  public function testGetPropertyId()
+  public function testGetPropertyId(): void
   {
     $id = str_replace('http://www.wikidata.org/prop/', '', $this->dummyProperties[0]['prop']);
 
     $this->assertEquals($id, $this->property->id);
   }
 
-  public function testGetPropertyLabel()
+  public function testGetPropertyLabel(): void
   {
     $this->assertEquals($this->dummyProperties[0]['propertyLabel'], $this->property->label);
   }
 
-  public function testGetPropertyValues()
+  public function testGetPropertyValues(): void
   {
     $values = $this->property->values;
 
-    $this->assertInstanceOf('Illuminate\Support\Collection', $values);
+    $this->assertInstanceOf(\Illuminate\Support\Collection::class, $values);
 
-    $this->assertInstanceOf('Wikidata\Value', $values->first());
+    $this->assertInstanceOf(\Wikidata\Value::class, $values->first());
   }
 }
diff --git a/tests/Unit/QualifierTest.php b/tests/Unit/QualifierTest.php
index e638ad4..2e0b6d6 100644
--- a/tests/Unit/QualifierTest.php
+++ b/tests/Unit/QualifierTest.php
@@ -13,19 +13,19 @@ public function setUp(): void
     $this->qualifier = new Qualifier($this->dummyProperties[0]);
   }
 
-  public function testGetQualifierId()
+  public function testGetQualifierId(): void
   {
     $id = str_replace('http://www.wikidata.org/entity/', '', $this->dummyProperties[0]['qualifier']);
 
     $this->assertEquals($id, $this->qualifier->id);
   }
 
-  public function testGetQualifierLabel()
+  public function testGetQualifierLabel(): void
   {
     $this->assertEquals($this->dummyProperties[0]['qualifierLabel'], $this->qualifier->label);
   }
 
-  public function testGetQualifierValue()
+  public function testGetQualifierValue(): void
   {
     $this->assertEquals($this->dummyProperties[0]['qualifierValueLabel'], $this->qualifier->value);
   }
diff --git a/tests/Unit/SearchResultTest.php b/tests/Unit/SearchResultTest.php
index 1c78f63..2e22b73 100644
--- a/tests/Unit/SearchResultTest.php
+++ b/tests/Unit/SearchResultTest.php
@@ -28,32 +28,32 @@ public function setUp(): void
     $this->result = new SearchResult($collection);
   }
 
-  public function testGetResultId()
+  public function testGetResultId(): void
   {
     $this->assertEquals($this->dummy['id'], $this->result->id);
   }
 
-  public function testGetResultLang()
+  public function testGetResultLang(): void
   {
     $this->assertEquals($this->dummy['lang'], $this->result->lang);
   }
 
-  public function testGetResultLabel()
+  public function testGetResultLabel(): void
   {
     $this->assertEquals($this->dummy['label'], $this->result->label);
   }
 
-  public function testGetResultWikiUrl()
+  public function testGetResultWikiUrl(): void
   {
     $this->assertEquals($this->dummy['wiki_url'], $this->result->wiki_url);
   }
 
-  public function testGetResultAliases()
+  public function testGetResultAliases(): void
   {
     $this->assertEquals($this->dummy['aliases'], $this->result->aliases);
   }
 
-  public function testGetResultDescription()
+  public function testGetResultDescription(): void
   {
     $this->assertEquals($this->dummy['description'], $this->result->description);
   }
diff --git a/tests/Unit/ValueTest.php b/tests/Unit/ValueTest.php
index 1deaaa3..4e2528a 100644
--- a/tests/Unit/ValueTest.php
+++ b/tests/Unit/ValueTest.php
@@ -13,24 +13,24 @@ public function setUp(): void
     $this->value = new Value($this->dummyProperties);
   }
 
-  public function testGetValueId()
+  public function testGetValueId(): void
   {
     $id = str_replace('http://www.wikidata.org/entity/', '', $this->dummyProperties[0]['propertyValue']);
 
     $this->assertEquals($id, $this->value->id);
   }
 
-  public function testGetValueLabel()
+  public function testGetValueLabel(): void
   {
     $this->assertEquals($this->dummyProperties[0]['propertyValueLabel'], $this->value->label);
   }
 
-  public function testGetValueQualifiers()
+  public function testGetValueQualifiers(): void
   {
     $qualifiers = $this->value->qualifiers;
 
-    $this->assertInstanceOf('Illuminate\Support\Collection', $qualifiers);
+    $this->assertInstanceOf(\Illuminate\Support\Collection::class, $qualifiers);
 
-    $this->assertInstanceOf('Wikidata\Qualifier', $qualifiers->first());
+    $this->assertInstanceOf(\Wikidata\Qualifier::class, $qualifiers->first());
   }
 }
diff --git a/tests/Unit/WikidataTest.php b/tests/Unit/WikidataTest.php
index 515b981..cd5875f 100644
--- a/tests/Unit/WikidataTest.php
+++ b/tests/Unit/WikidataTest.php
@@ -7,22 +7,22 @@
 
 class WikidataTest extends TestCase
 {
-  protected $wikidata;
+  protected Wikidata $wikidata;
 
   public function setUp(): void
   {
     $this->wikidata = new Wikidata();
   }
 
-  public function testSearchByTerm()
+  public function testSearchByTerm(): void
   {
     $results = $this->wikidata->search('London');
 
-    $this->assertInstanceOf('Illuminate\Support\Collection', $results);
+    $this->assertInstanceOf(\Illuminate\Support\Collection::class, $results);
 
     $result = $results->first();
 
-    $this->assertInstanceOf('Wikidata\SearchResult', $result);
+    $this->assertInstanceOf(\Wikidata\SearchResult::class, $result);
 
     $this->assertEquals(true, property_exists($result, 'id'));
     $this->assertEquals(true, property_exists($result, 'lang'));
@@ -32,38 +32,39 @@ public function testSearchByTerm()
     $this->assertEquals(true, property_exists($result, 'wiki_url'));
   }
 
-  public function testSearchOnAnotherLanguage()
+  public function testSearchOnAnotherLanguage(): void
   {
     $results = $this->wikidata->search('London', 'fr');
 
     $this->assertEquals('fr', $results->first()->lang);
   }
 
-  public function testSearchWithLimit()
+  public function testSearchWithLimit(): void
   {
     $results = $this->wikidata->search('car', 'en', 10);
 
     $this->assertEquals(10, $results->count());
   }
 
-  public function testSearchResultsCouldBeEmpty()
+  public function testSearchResultsCouldBeEmpty(): void
   {
     $results = $this->wikidata->search('asdfgh');
 
-    $this->assertInstanceOf('Illuminate\Support\Collection', $results);
+
+    $this->assertInstanceOf(\Illuminate\Support\Collection::class, $results);
 
     $this->assertEquals(true, $results->isEmpty());
   }
 
-  public function testSearchByPropertyIdAndValue()
+  public function testSearchByPropertyIdAndValue(): void
   {
     $results = $this->wikidata->searchBy('P646', '/m/02mjmr');
 
-    $this->assertInstanceOf('Illuminate\Support\Collection', $results);
+    $this->assertInstanceOf(\Illuminate\Support\Collection::class, $results);
 
     $result = $results->first();
 
-    $this->assertInstanceOf('Wikidata\SearchResult', $result);
+    $this->assertInstanceOf(\Wikidata\SearchResult::class, $result);
 
     $this->assertEquals(true, property_exists($result, 'id'));
     $this->assertEquals(true, property_exists($result, 'lang'));
@@ -73,36 +74,36 @@ public function testSearchByPropertyIdAndValue()
     $this->assertEquals(true, property_exists($result, 'wiki_url'));
   }
 
-  public function testSearchByThrowExceptionIfSecondPropertyMissing()
+  public function testSearchByThrowExceptionIfSecondPropertyMissing(): void
   {
     $this->expectException(Exception::class);
 
     $this->wikidata->searchBy('P646');
   }
 
-  public function testSearchByThrowExceptionIfPropertyIdInvalid()
+  public function testSearchByThrowExceptionIfPropertyIdInvalid(): void
   {
     $this->expectException(Exception::class);
 
     $this->wikidata->searchBy('Pasd', '/m/02mjmr');
   }
 
-  public function testSearchByPropertyIdAndEntityId()
+  public function testSearchByPropertyIdAndEntityId(): void
   {
     $results = $this->wikidata->searchBy('P39', 'Q11696');
 
-    $this->assertInstanceOf('Illuminate\Support\Collection', $results);
+    $this->assertInstanceOf(\Illuminate\Support\Collection::class, $results);
 
     $result = $results->first();
 
-    $this->assertInstanceOf('Wikidata\SearchResult', $result);
+    $this->assertInstanceOf(\Wikidata\SearchResult::class, $result);
   }
 
-  public function testGetEntityById()
+  public function testGetEntityById(): void
   {
     $entity = $this->wikidata->get('Q44077');
 
-    $this->assertInstanceOf('Wikidata\Entity', $entity);
+    $this->assertInstanceOf(\Wikidata\Entity::class, $entity);
 
     $this->assertEquals(true, property_exists($entity, 'id'));
     $this->assertEquals(true, property_exists($entity, 'lang'));
@@ -112,14 +113,14 @@ public function testGetEntityById()
     $this->assertEquals(true, property_exists($entity, 'wiki_url'));
   }
 
-  public function testGetEntityOnAnotherLanguage()
+  public function testGetEntityOnAnotherLanguage(): void
   {
     $entity = $this->wikidata->get('Q44077', 'es');
 
     $this->assertEquals('es', $entity->lang);
   }
 
-  public function testGetEntityThrowExceptionIfEntityIdInvalid()
+  public function testGetEntityThrowExceptionIfEntityIdInvalid(): void
   {
     $this->expectException(Exception::class);